A service at Sydney’s Pitt Street Uniting Church was interrupted in dramatic fashion on Sunday morning, when two protesters rose to criticise the church over its vocal stance in support of same-sex marriage.

The protest comes in the dying days of Australia’s postal survey on same-sex marriage, which has engendered enthusiastic, and at times ugly, debate across the nation on whether same-sex couples should be allowed to marry.

About 80 parishioners were gathered for a regular service on Sunday morning at the Pitt Street church, when a man who does not usually attend the church approached the open prayer microphone.

“It was really clear he was talking about the banner we have outside saying we support marriage equality. He said that was wrong, contrary to the word of God, and proceeded to read some scripture passages. I let him read one and then I asked him to stop.

“He read 1 Corinthians 6:9, a bad translation in my view. The translation he read has the word homosexuality, but it’s one of those Greek words that means a whole range of things ... He mentioned something also from Romans, and I knew where he was heading.”

Mayman was prepared for such an incursion — the church had put plans in place after an aggressive, agitated man walked in last month, also taking issue with its visible support for same-sex marriage. But when people calmly approached the man at the microphone and asked him to leave, a second protester stood up, yelling.

“She shouted and denounced the congregation’s stance on [marriage], and waved her Bible at us,” Mayman said.

So the church organist launched into a song – For Everyone Born, A Place At The Table – to briefly drown out the ruckus while the protesters were removed and the service continued.

The song, which Mayman described as a "wonderful anthem of inclusiveness", was sung earlier in the service, including this optional verse:

For gay and for straight, a place at the table,

a covenant shared, a welcoming space,

a rainbow of race and gender and colour

for gay and for straight, the chalice of grace.

Now, the church is planning to keep that song in the printed literature for services in the coming weeks, in case another protest happens.

People at Pitt Street are unsure who the man and woman are and whether they are associated with any group. However, video footage from a camera installed in the foyer showed the pair arriving together.

Mayman, who is a lesbian, said it was "obviously distressing" that people trying to worship would be disrupted in this way.

"I’m amazed that people can feel that was an appropriate thing to do," she told BuzzFeed News. "I’m always open to having a conversation with people, and it was completely unnecessary for them to use that worship service to come and make their point.

"We would never do anything like that to churches or people who feel differently than we do. I was upset for people I know who are LGBTI in the congregation who are already enduring the postal survey, and having our lives and relationships be the subject of the discussion around it."

Mayman said many of the older people in the congregation were struggling with the survey, as it brought back memories of life in Australia before homosexuality was decriminalised, as well as bad experiences of discrimination at work and in life.

"We all believe that the love and acceptance and care that exists and has existed here over the years is stronger than one incident of somebody coming out and being intolerant and judgemental – not to mention using bad Biblical interpretations."

Churches have been something of a battleground in the postal survey campaign, with two Melbourne churches sprayed with graffiti reading “crucify no voters” and “bash bigots” in October.